The food induced midgut proteases of the cockroach Leucophaea maderae will be further purified and characterized by their physico-chemical properties. Following complete purification antibodies to the various proteases will be prepared. This will then allow the development of a sensitive radioimmune assay and also the location of the enzymes and site of production in the midgut epithelia. The mode of protease induction will further be investigated in detail. Radiolabeling of the proteases suggests de novo synthesis in the midgut epithelium. Synthesis of the proteases in the midgut epithelia will be studied in organ cultures following passage of proteins through the gut by artificial means. The mode of synthesis and secretion of the proteases by membrane-bound polysomes will be investigated. The function of the peritrophic membrane and its properties is of interest in this context. Rates of synthesis of this membrane in starved and fed animals, its permeability characteristics for macromolecules, and its composition will be studied.